Blade control apparatus of a motor grader, as for example shown in U.S. Pat. No. 3,561,538 which issued Feb. 9, 1971 to Curlitt from an application filed Aug. 25, 1969, has an actuating wand that is associated with a reference line. The wand travels along the reference line during grading operations and the grader blade is maintained substantially parallel with the reference line in response to the actuating wand of the control apparatus being vertically moved by the reference line.
Since the reference line is usually a wire line extending along the area to be graded and is supported by stakes driven into the ground, the actuating wand sometimes impacts a stake. This impact is sometimes relatively severe when the grading speed is high and/or the stake is improperly oriented.
Although the associated blade control apparatus for the wand has vibration damping dash pots or other means, it has been determined that supplemental stabilizing means can improve the performance of the control means by damping out sudden impact forces while permitting the control apparatus to be maintained relatively sensitive to continuing force subjected on the wand by elevation changes of the reference line.
This invention therefore resides in improved control apparatus for damping vibrations of an actuating wand of blade control apparatus of a motor grader.